1. Field of the Invention
The present general inventive concept relates to a moving picture experts group (MPEG) surround system, and more particularly, to an MPEG surround binaural decoder to decode an MPEG surround stream into a 3-dimensional (3D) stereo signal, and a decoding method thereof.
2. Description of the Related Art
In general, an MPEG surround system compresses multi-channel audio data having N channels into multi-channel audio data having M channels (M<N), and uses additional information, to restore the compressed audio data again to the multi-channel audio data that has N channels.
A technology related to this MPEG surround system is disclosed in WO 2006/014449 A1 (PCT/US2005/023876), filed on 5 Jul. 2005, entitled CUED-BASED AUDIO CODING/DECODING.
FIG. 1 is a block diagram illustrating a conventional MPEG surround system. Referring to FIG. 1, an encoder 102 includes a downmixer 106 and a binaural_cue coding (BCC) estimation unit 108. The downmixer (e.g. “downmix C-to-E) 106 transforms input audio channels (Xi(n)) into audio channels (yi(n)) to be transmitted. The BCC estimation unit 108 divides the input audio channels (Xi(n)) into time-frequency blocks, and extracts additional information existing between channels in each block, i.e., an inter-channel time difference (ICTD), an inter-channel level difference (ICLD), and an inter-channel correlation (ICC).
Accordingly, the encoder 106 downmixes multi-channel audio data having N channels into multi-channel audio data having M channels, and transmits the audio data together with additional information to a decoder 104.
The decoder 104 uses downmixed audio data and additional information to restore the multi-channel audio data having N channels.
In the conventional MPEG surround system as illustrated in FIG. 1, an MPEG surround stream is decoded into multi-channel audio data with 5.1 or more channels. Accordingly, a multi-channel speaker system is required to reproduce this multi-channel audio data.
However, it is difficult for a mobile device to have a multi-channel speaker system. Accordingly, the mobile device cannot reproduce the MPEG surround system effectively.